In general, there are two complementary approaches to manufacturing an object: additive manufacturing and subtractive manufacturing.
Additive manufacturing involves aggregating material to form the desired object. In contrast, subtractive manufacturing involves removing material to form the desired object. In practice, many objects are manufactured using a combination of additive and subtractive techniques.
A form of additive manufacturing—colloquially known as “three-dimensional (3D) printing”—is the subject of intense research and development because it enables objects with complex geometries to be manufactured without molds or dies. Furthermore, 3D printing enables the mass customization of objects with different dimensions and characteristics.
In at least one 3D printing technique, the object is built by providing a thermoplastic filament to a deposition head on a robotic arm. The thermoplastic filament comprises a continuous tow of carbon fibers that is impregnated with thermoplastic. The deposition head heats and deposits the thermoplastic filament as one or more runs of material, via a roller. After it is deposited, each run quickly solidifies and fuses with the runs that it touches. The technique builds a three-dimensional object from a mathematical model of the object.
In order to build the object to within the tolerances specified in the model, the deposition head must continuously provide proper guidance of the filament to the correct positions on the object being manufactured. At the same time, in order to heat the thermoplastic while not adversely affecting the carbon fibers in the filament, the deposition head must heat the filament correctly. The deposition head does this typically by providing sufficient exposure of the filament to a directed and carefully regulated heat source. However, exposing the filament too much, for heating purposes, can result in the filament traveling unrestricted over a significant distance, in particular from the heated portion to the roller, potentially and adversely affecting the build quality of the object being manufactured.
What is needed is a system for guiding the filament to the correct positions on the object being manufactured, without at least some of the disadvantages in the prior art.